Installing as an rbenv plugin (recommended)

This will install the latest development version of ruby-build into
the ~/.rbenv/plugins/ruby-build directory. From that directory, you
can check out a specific release tag. To update ruby-build, run git pull to download the latest changes.

Installing as a standalone program (advanced)

Installing ruby-build as a standalone program will give you access to
the ruby-build command for precise control over Ruby version
installation. If you have rbenv installed, you will also be able to
use the rbenv install command.

This will install ruby-build into /usr/local. If you do not have
write permission to /usr/local, you will need to run sudo ./install.sh instead. You can install to a different prefix by
setting the PREFIX environment variable.

To update ruby-build after it has been installed, run git pull in
your cloned copy of the repository, then re-run the install script.

Installing with Homebrew (for OS X users)

Mac OS X users can install ruby-build with the
Homebrew package manager. This
will give you access to the ruby-build command. If you have rbenv
installed, you will also be able to use the rbenv install command.

This is the recommended method of installation if you installed rbenv
with Homebrew.

$ brew install ruby-build

Or, if you would like to install the latest development release:

$ brew install --HEAD ruby-build

Usage

Using rbenv install with rbenv

To install a Ruby version for use with rbenv, run rbenv install with
the exact name of the version you want to install. For example,

$ rbenv install 1.9.3-p194

Ruby versions will be installed into a directory of the same name
under ~/.rbenv/versions.

To see a list of all available Ruby versions, run rbenv install --list.
You may also tab-complete available Ruby
versions if your rbenv installation is properly configured.

Using ruby-build standalone

If you have installed ruby-build as a standalone program, you can use
the ruby-build command to compile and install Ruby versions into
specific locations.

Run the ruby-build command with the exact name of the version you
want to install and the full path where you want to install it. For
example,

$ ruby-build 1.9.3-p194 ~/local/ruby-1.9.3-p194

To see a list of all available Ruby versions, run ruby-build --definitions.

Pass the -v or --verbose flag to ruby-build as the first
argument to see what's happening under the hood.

Custom definitions

Both rbenv install and ruby-build accept a path to a custom
definition file in place of a version name. Custom definitions let you
develop and install versions of Ruby that are not yet supported by
ruby-build.

Special environment variables

You can set certain environment variables to control the build
process.

TMPDIR sets the location where ruby-build stores temporary files.

RUBY_BUILD_BUILD_PATH sets the location in which sources are
downloaded and built. By default, this is a subdirectory of
TMPDIR.

CC sets the path to the C compiler.

CONFIGURE_OPTS lets you pass additional options to ./configure.

MAKE_OPTS (or MAKEOPTS) lets you pass additional options to
make.

Keeping the build directory after installation

Both ruby-build and rbenv install accept the -k or --keep
flag, which tells ruby-build to keep the downloaded source after
installation. This can be useful if you need to use gdb and
memprof with Ruby.

Source code will be kept in a parallel directory tree
~/.rbenv/sources when using --keep with the rbenv install
command. You should specify the location of the source code with the
RUBY_BUILD_BUILD_PATH environment variable when using --keep with
ruby-build.

20110914

Added support for setting ./configure options with the
CONFIGURE_OPTS environment variable.

Added a 1.9.3-dev definition for Ruby 1.9.3 from Git.

Added support for fetching package sources via Git.

Added an rbenv-install script which provides an install command
for rbenv users.

20110906.1

Changed the REE definition not to install its default gem
collection.

Reverted a poorly-tested change that intended to enable support for
relative installation paths.

20110906

Initial public release.

License

(The MIT License)

Copyright (c) 2011 Sam Stephenson

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.